An older, "fuller" brain; microbes make babies cry

THE OLDER BRAIN IS WILLING, BUT FULL
Learning becomes more difficult as we age, not because of trouble absorbing new information, but because we fail to forget the old stuff, researchers say.

Mice whose brains were genetically modified to resemble those of adult humans showed no decrease in the ability to make the strong synaptic connections that enable learning — a surprise to neuroscientists at the Medical College of Georgia at Georgia Regents University, whose findings appear in Scientific Reports.

Yet as the modified mice entered adulthood, they were less capable of weakening connections that already existed, and that made it hard to form robust new long-term memories. Think of it as writing on a blank piece of paper versus a newspaper page, said the lead author, Joe Z. Tsien.

“The difference is not how dark the pen is,” he said, “but that the newspaper already has writing on it.”

— Douglas Quenqua, The New York Times

MICROBES LINKED TO BABIES’ COLIC CRIESNo one knows what causes colic, the intense pain and stomach cramping that commonly begins in otherwise healthy infants at about a month and disappears a few months later. But now researchers have found a possible explanation: the kinds of microbes in babies’ intestines.

Researchers in the Netherlands collected stool samples from 12 colicky babies and 12 age-matched babies without colic over their first 100 days of life. All babies and mothers were healthy. But the scientists found significant differences in the intestinal microbes of colicky and noncolicky babies. Those with colic had more proteobacteria — including species that produce gas and inflammation — and fewer bifidobacteria, especially the lactobacilli known to combat inflammation.

The researchers, writing in Pediatrics, suggest that probiotic supplements, which contain beneficial bacteria and sometimes decrease symptoms, may work by displacing harmful bacteria. But the lead author, Carolina de Weerth, cautioned against routinely giving probiotics to infants.

“We actually haven’t determined causality,” she said. “We need randomized controlled studies to see if there’s a causal effect and to see if it’s safe.”

— Nicholas Bakalar, The New York Times

Last modified: January 28, 2013
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